Cool. But note that this is not a problem that you're likely to run into in practice. Nolan and Gelman claim that you can't actually bias a coin.
Basically, it proves that creating a biased coin really is impossible.
TL;DR: if you want unbiased coin IRL, make sure you catch it before it hits the ground.
one cannot, for example, weight a coin so that it is substantially more likely to land “heads” than “tails” when flipped and caught in the hand in the usual manner. Coin tosses can be biased only if the coin is allowed to bounce or be spun rather than simply flipped in the air.